Miniature switch



April 18, 1961 E. J. NABQSTEDT MINIATURE SWITCH 2 Sheets-Sheet 1 Filed Dec. 18, 1958 A lfl FIG. IQ

ELMER J'. NABSTEDT INVENTOR. BY M h M April 18, 1961 E. J. NABSTEDT 2,980,770

MINIATURE SWITCH Filed Dec. 18, 1958 2 Sheets-Sheet .2

zol IOSb FIG. l5

ELMER I NABSTEDT MM; r

United States MINIATURE swrrcn Elmer J. Nabstedt, Westwood, N.J., assignor to The Daven Company, Livingston, NJ., a corporation of New Jersey Filed Dec. 18, 1958, Ser. No. 781,282

18 Claims. (Cl. 200-11) The present invention seeks to overcome this problem by providing an improved fluid tight miniature switch characterized by the placement of a detent means, a stop arrangement and movable contacts in close-coupled arrangement on a rotatable shaft to permit the movable contacts to coast with the stationary contacts whereby a wide range of switch contact positions both of the single and multi-pole variety are provided in an arrangement which is relatively simple to manufacture and assemble.

Accordingly, it is an object of the present invention to provide a miniature switch adapted to provide optimum efficiency and reliability for the conditions under which it is required to operate.

It is another object of the present invention to provide a miniature multi-positioned switch adapted either for single-pole or mul-ti-pole operation.

Further objects' and advantages of-the invention will become evident fro-m the following description with ref- I erence to the accompanying drawings in which:

Figure l is a side elevation of a single-pole-multi-position switch.

Figure 2 is a vertical'scotion through a single-polernulti-posi-tion switch.

Figure 3 is an exploded view in vertical section showing the various elements and their relative relation in a single-ple-multi-position switch showing the invention.

Figure 4 is a view taken on line 4-4of Figure 3.

Figure 5 is a cross-section taken on line 55 of Figure 2. I V

Figure 6 is a cross-seotion taken on line 6--6 of Figure 2 showing one position of the detent.

Figure 7 is an end view showing one form of hub for supporting the movable contact.

Figure 8 is a perspective view of the detent sleeve.-

Figure 9 is a viewsimilar to Figure 4 of the stationary contacts of a multi-pole-mnltiposition switch.

Figure 10 is a view of another form of hub forsupporting the movable contacts. I

Figure 11 is a fragmentary view partly in section of the center contact means. for a multi-pole-multi-position switch.

Figure 12 is-a view similar to Figure 4 showing a modified form of stationary contact for a break before make switch I of the single-pole-multi-position type.

atent Figure 13 is a cross-section taken on line 13-13 of Figure 12.

Figure 15 is a cross-section taken on line 15---15 of Figure 14.

Referring more particularly to the drawing, Figures 1, 2, 3 and 4 show one form of the switch wherein the housing 1 is a substantially cylindrical-shaped vessel with an end wall 2 and a stationary contact panel 3 made of any suitable insulating material closing the end of the housing remote from the end wall 2 to form a switch assembly chamber generally designated 4.

A boss 5 projects from the end wall 2 in the axial line of the switch. Bore 6 through the boss 5 and end wall 2 opens into the assembly chamber 4 at the end remote from the stationary control panel 3 so that the operating shaft 7 may be rotatably mounted in the bore 6 and extend into the assembly chamber '4 the desired predetermined distance to provide means for mounting thereon a detent assembly generally designated A, a stop assembly generally designated B, and a movable contact assembly generally designated C, in the order named, which assemblies are more fully described hereinafter.

The shaft extends outwardly of the boss 5 a suificient distance so that when the switch is in assembled relation to a control panel as by the threaded means 8 and a nut (not shown) means may be attached thereto for manually rotating the shaft and the various assemblies mounted thereon.

It is noted that O-type seals are provided in the bore 6 about the shaft as at 9 and 10 so that the chamber 4 is fluid sealed. Similarly, when the stationary contact panel 3 is afiixed to the end of thehousing remote from the control panel connecting end, a suitable material such as an epoxy resin shown at 12 may be used to seal the joint between the contact panel 3 and the inner wall of the housing. This material also seals the stationary contacts, more fully described below, which extend through the contact panel 3. 7

An O-ring may be provided on the face of the end wall 2 as at ll to provide a fiuid tight seal between the switch and the point of attachment on the control panel.

, The detent assembly The detent assembly A includes the enlarged circular hub 20 formed on the shaft 7 which hub has a diameter such that a transverse passage 21 may be formed therein to receive ball elements 2 2 and 23 and a spring 24 which vent the sleeve from rotating in position.

The detent sleeve 25 is shown in perspective. in Figure 8 of the drawings asa hollow cylindrical element with a plurality of circumferentially spaced ridges 27 and grooves 26 formed just inwardly of one end which gives the end a zig-zag or corrugated appearance. As clearly shown in Figures 3 and 8 of the drawings'one of the ridges 28 has a longer axiallength than any of the other ridges 27; This ridge co-acts with the stop assembly B i as hereinafter described; and also is engaged by the dimpled portion 25a of the hcusingto prevent rotation of the detent sleeve 25 in assembled position.

" Fig re 5 shows that in assembled position the balls 22 'and 23 are disposed to engagethe grooves when manna -is rotated in either direction, the various positions of ithe index from groove switch being determined as the balls to groove. Y

3 Figure 3 further shows that the shaft 7 is necked-down outwardly of the hub 20 to provide a projection 30 which receives the stop assembly B and the movable contact assembly C thereon. These assemblies are held on the noperating shaft 7 by any suitable means such as peaning the end of the shaft as at 31 into'snug engagement with the inner wall of-the movable contact assembly.

Stop assembly The stop assembly is shownin this form of the invention as including two disc elements 41 and 42 shown in Figures 3 and 6 of the drawings. Each of the disc elements are substantially fiat with a radial projection as at I transverse end wall 53 which grooves have slots 57 ex- 43 and 44 and a centrally disposed opening 45 to provide means for mounting the discs on the projection 30 adjacent the hub 20 formed on the shaft 1.

At least one of the discs is provided with a plurality of spaced openings 46 just inwardly of its peripheral edge and the other of said discs with at least a single opening so that when the dism are mounted on the projection 30 the radial projections 43 and 44 can be set in a given number of positions relative to each other and held in these adjusted positions by means of the assembly setting pin 48 which also engages the cylindrical portion as at 49 and the movable contact assembly C as at 50 so that the detent mechanism, the stop assembly and the movable contacts can be held in any desired position relative to each other.

In assembled position the radial projections 43 and 44 will be disposed relative the circular portion 20 as indicated in Figures 3 and 6 to engage the single axiallyextending ridge 28 which is the only ridge in'the detent sleeve 25 which extends axially beyond the outer edge of the hub 20. On rotation of the shaft 7 the stop assembly will have one limit position wherein the radial projection 43 is brought into contact with the ridge 28 and in the opposite direction another limit position wherein projection 44 will be brought into engagement with the ridge 28. Thus any desired span degree of rotation is obtainable depending upon the number. of holes 46 .and the relative positions at which the discs 41 and 42 are set in assembled position.

While this type of stop assembly is shown and de scribed, it is believed clear that those skilled in the art will understand that a single disc member of a diameter only slightly less than the inner diameter of the cylindrical portion of the detent sleeve 25 with an arcuate section cut in its periphery to form the desired stop limits may also be used. However, this arrangement would not have the versatility of the above described assembly and would require many separate discs for each of the various angular stop limits that may be desired for the switch. a

In a continuous rotation switch the stop means may be omitted.

- Movable contact assembly relative position of the detent mechanism, the stop asgsembly and the movable contact assembly is determined I by means of the assembly setting pin 48. 1:

Figure 7 shows that the annular portion52 of th carrier element 51 has a plurality of axially disposed tending axially inwardly from the bottoms 58 to provide means for mounting the movable contact elements 60 in the hub 51.

The movable contact elements 60 are made of any suitable current-conducting material which has some degree of resiliency so that when the unit is folded on itself it will form a stem as at 61 to be forced into snug engagement with the slots 57 in the respective grooves 55 and 56.

' The movable contact elements 60 also have cup-shaped contact surfaces 62 formed at their respective ends which are shown in Figure 3 as extending laterally of the respective inner and outer walls of the annular cylindrical portion 52 of the hub 51 when in assembled position.

.The natural or inherent resiliency of the material of which the movable contact element is made will permit the cup-shaped portions 62 of the contact elements to make firm contact in assembled position with the stationary contacts formed on the stationary contact panel 3 as hereinafter described.

In Figure 10 there is ilustrated a modified form of the construction shown in Figure 7. In this figure, the carrier 51a has grooves 56a, 56b and 550, and each groove is provided with a slot 57a. Grooves 56a, 56b and 56c are arranged in this form of the invention at substantially l08 to each other and provide for the placing of contact members as previously described for the form of the invention shown in Figures 1 to 9 of the drawings. Similarly, the carrier 51a shown in Figure 10 may be provided with a positioning aperture 50a as previously described for the reception of the pin 48.

Stationary contact panel The stationary contact panel 3 alsoshown in Figures .3 and 4 is a flat disc-like member which may be made of any suitable insulating material.

'Inwardly of the periphery of the stationary contact panel 3 are a plurality of circumferentially spaced axially extending stationary contacts 63a, 63b, 630, etc. mounted in and locked to the panel.

In assembled position the inner portion 65a, 65b, 650, etc. of the respective stationary contacts will be disposed in the switch assembly chamber 4 and the outer portions 66a, 66b, 66c, disposed exteriorly of the switch. Suitable connections can be made from the circuit to the switch by means of the outer portions 66a, 66b, 660, etc. in the manner well known in the art.

In the form of the invention illustratedin Figures 1 to 7 of the drawings a single pole 67 is shown mounted in the contact panel 3 in the axial line of the switch. This centrally disposed pole is made of any suitable currentconducting material and includes a'cylindrical contact surface 67a extending into the switch assembly chamber which is sized to provide a predetermined radially spaced distance between the inner portions 65a, 65b, 650 of the respective stationary contacts 63a, 63b, 63c, etc. and the outer surface of the cylindrical contact surface 67a so that in assembled position the spherical contact faces of the movable contact elements 60 will be squeezed into this space vand make firm contact with the respective inner portions 65a, 65b, 650, etc'. of the stationary contacts and the cylindrical contact surface'67a of the center pole 67.

Figures 4 to 7 show that the centrally disposed contact means comprises a single solid element. However, the stationary contact panel may be modified as suggested in Figures 9 and 11 of the drawings wherein the centrally disposed elements are split into a plurality of angularly spaced contact members '79, 71 and 72 which extend through the contact panel designated 73 for the modified 7 'form of the invention.- lnwardly of the periphery of .grooves 55 and 56 cut inwardly from the face ofihe L portion remote from the face connected the contact panel there is also a plurality of stationary J contacts 74. The respective stationary contacts 74 are to. the 75 a predetermined radially spaced distance from the centrally disposed contact so that in assembled position as in the form of the invention shown in Figures '1 to 8 the movable contacts 60 will be squeezed therebetween to make firm contact.

These members 70, 71 and 72 have the sections 70a, 71a and 72a that will be disposed in the notch assembly chamber 4 so shaped that the surfaces are disposed in alignment with the respective surfaces of the inner portion 74 of the plurality of stationary contact elements 74. The sections 70b, 71b, 72b of the centrally disposed elements and 74b of the respective stationary contacts extend outwardly of the switch assembly chamber to provide means for connecting the switch to the circuit with which it cooperates.

In the form of the invention above described a shorting type switch of the make before break type is illustrated. In a make before break type switch the movable contact element 60 will be in contact at certain portions of its rotation with two of the stationary contacts thus shorting the circuits between these contacts.

It is believed that those skilled in the art will recognize that if only every other stationary contact is utilized or any other similar mechanical expediency is used that a non-shorting or break before make type switch will be provided.

Figures 12, 13, 14 and 15 for example show one means for accomplishing this result for either single or multipole, multi-position switches wherein the stationary contact panel is altered to provide the desired result.

This variation in the construction of the stationary contact panel will, as is easily understood by those skilled in the art, also require changes in the other elements coacting therewith, namely, the movable contact assembly, the stop means and the detent sleeve, insofar as the angular placement of the parts are concerned. For example, the movable contact elements 60 in the cylinder portion 52 of the hub 51 will in a three-contact hub be moved from 108 to 120 spacing to coact with the contacts in the stationary contact panels shown in Figures 12, 13, 14 and 15.

In Figures 12 and 13, a single-pole-multi-position break before make type arrangement is shown wherein the stationary contact panel 103 is a flat disc-like member made of any suitable insulating material.

As in the case of a make before break type arrangement above described and shown in Figures 1-l1, we find inwardly of the periphery of the stationary contact panel 103, a plurality of circumferentially spaced axially or longitudinally disposed contact elements which are fixedly mounted in the panel and extend therethrough so that in assembled position the inner portions 104a, 104b, 1104c etc. of the respective stationary contacts will be in the switch assembly chamber 4 and the outer portions 105a, 105b, 1050, etc. disposed exteriorly of the switch. Suitable connections can be made from the circuit to the switch by means of the outer portions 105a, 105b,,105c, etc. Since Figures 12 and 13 illustrate a single-pole stationary contact panel, only a single pole 106 is shown disposed centrally or along the axial line of the switch with respect to the stationary contact elements.

This centrally disposed pole 106 is made of any suitable current-conducting material and includes a cylindrical inner portion 106a extending into the switch assembly chamber in assembled position and an outer portion Gb disposed exteriorly with respect to the switch. The inner contact surface 106a is sized to provide a radially spaced distance between the inner positions 104a, 104b, 1040, etc,'of the stationary contacts mounted inwardly of the periphery of the panel 103 and the outer surface of the cylindrical inner portion 106a of the center pole 106 so that in assembled position the spherical contact faces of the movablecontactelements 60 will be squeezed into this space and make firm contact with the respective portions of the stationary contacts.

In order to provide the desired break before make type operation, the inner portions 104a, 104b, 104e, etc. of the stationary contact elements will be spaced a suflicient distance from each other to insure that the movable contact elements 60 will not rest simultaneously on any two inner portions 104a, 104b, 104s, etc, of the stationary contacts at the same time.

The presence or" this gap alone, however, will not accomplish this result. A plurality of spacer elements 107 must be provided between each pair of the inner portions M411, ihdb, iii is, etc. to provide smooth operation and movement for the movable contact elements 60'.

The spacer elements 107 are mounted in the panel 103 and in assembled position extend axially into the switch assembly chamber and these spacers are sized with respect to the inner portions 104a, 104b, 1040, etc. of the stationary contact elements so that a maximum number of contacts can be provided for the switch and the desired break before make type operation obtained. Sizing is of course primarily therefore a matter of geometry to provide the best arrangement.

In Figures 14 and 15, a multi-pole, multi-position break before make type arrangement is shown which differs from that above described for Figures 12 and 13 in that the center contact means has a multiplicity of inner contact portions as at 201a, 201b and 2010, with corresponding outer portions 202a, 202b, etc.

All remaining elements of this form of the invention are identical with that above described for the form of the invention shown in Figures 12, 13 and 14.

The inner portions 201a, 2011) and 2010, etc. will b sized and spaced relative the inner portions 104a, 104b, 1040, etc. of the stationary contacts mounted inwardly of the periphery of the contact panel 103 to provide the desired annular space into which the movable contact 60 will be squeezed in assembled position.

As indicated above, the relative geometry between the inner portions ltF-ta, 104b, 1040, etc. and the spacers 107 will be adjusted to obtain maximum contact element positions. This in turn is correlated with the positioning of the movable contacts 60, the stop limits, and the ridges or grooves of the detent sleeve to give the desired operation.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown but that they may be widely modified within the invention defined by the claims.

What is claimed is: v

1. In a miniature switch, a housing forming a chamber open at one end, a contact panel closing the open end of said chamber, a shaft rotatably mounted in said housing and extending into said chamber, a plurality of circumferentially spaced stationary contacts in said contact panel disposed to extend therethrough into the chamber, center contact means in said contact panel disposed relative said stationary contacts in said chamber to form an annular space therebetween, said stationary contacts and said center contact means to provide a predetermined switching arrangement, a movable contact assembly means mounted on the end of said shaft including a carrier, said carrier having contact means thereon disposed to fit into said annular space'for simultaneous contact with said stationary contacts and said center contact means to provide a predetermined switching arrangement on rotation of said shaft, detent means in said chamber to permit step by step indexing of said shaft during-rotation, stop means in said chamber to limit the degree of rotation of said shaft in either direction, and means detachably connected to the stop means and said last mentioned means connecting the detent means to one side of the stop means and connecting the movable contact assembly to the otherside of the stop means whereby the detent means, stop means and movable contact assembly are in fixedpredetermined relation to provide a desired switching arrangement on rotation of said shaft.

2. In a miniature switch as claimed in claim 1 wherein said plurality of stationary contacts are spaced a predetermined distance from each other, and spacer means between adjacent stationary contacts to provide a break before make type arrangement.

3. In a miniature switch, a housing forming a chamber open at one end, a contact panel closing the open end of said chamber, a shaft rotatably mounted in said housing and extending into said chamber in overhung relation to bring the end a predetermined spaced distance from the contact panel, a plurality of circumferentially spaced stationary contacts in said contact panel disposed to extend therethrough into the chamber, center contact means in said contact panel extending into said chamber, said stationary contacts and said center contact means disposed to form an annular space therebetween, said stationary contacts and said center contact means to provide a predetermined switching arrangement, a movable contact assembly means mounted on the end of said shaft including a carrier element having a cylindrical portion disposed to fit into said annular space in assembled position, and at least one contact means on said cylindrical portion adapted to engage said stationary contacts and said center contact means on rotation of the shaft.

4. in a miniature switch, a housing forming a chamber open at one end, a contact panel closing the open end of said chamber, a shaft rotatably mounted in said housing and extending into said chamber, a plurality of circumferentially spaced stationary contacts in said contact panel disposed to extend therethrough into the chamber, center contact means in said contact panel extending into said chamber, said stationary contacts and said center contact means disposed to form an annular space therebetween, said stationary contacts and said center contact means to provide a predetermined switching arrangement, a movable contact assembly means mounted on the end of said shaft including, a carrier element having a cylindrical portion disposed to fit into said annular space in assembled position, and at least one contact means in said cylindrical portion adapted to engage said stationary contacts and said center contact means on rotation of the shaft, detent means including a circular hub, plural detent elements in the circular hub and biased to move outwardly thereof, and a detent sleeve mounted in said chamber having alternately spaced ridges and grooves to coact with said detent elements to permit step by step indexing of said movable contact assembly means on rotation of said shaft. r

5. In a miniature switch as claimed in claim 4 wherein said plurality of stationary contacts are spaced a predetermined distance from each other, and spacer means between adjacent stationary contacts to provide a break before make type arrangement.

6. In a miniature switch, a housing forming a chamber open at one end, a contact panel closing the open end of said chamber, a shaft rotatably mounted in said housing and extending into said chamber in overhung relation to bring the end of said shaft a predetermined spaced distance from the contact panel, a plurality of circumferen tiaily spaced stationary contacts in said contact panel disposed to extend therethrough into the chamber, center contact means in said contact panel extending into'said chamber, said stationary contacts and said center contact means disposed to form an annular space therebetween, and movable contact assembly means mounted on the end of said shaft including a carrier element having a cylindrical portion disposed to fit into said annular space in assembled position, and spaced contact means in said cylindrical portion adapted to engage said stationary contacts and said center contact means on rotation of the biased to move outwardly thereof, and a detentsleeve having alternately spaced ridges and grooves about said 8 detent means to coact with said detent elements, at least one of said ridges extending beyond the end of said enlarged circular hub to form a stop; shoulder, adjustable stop means mounted on said shaft between said detent means and said movable contact assembly to coact with the stop shoulder for limiting the rotation of said shaft in either direction, and means connecting the detent means, the stop means and the movable contact assembly means in a predetermined fixed relation to provide a pre determined switching arrangement on rotation of said shaft.

7. in a miniature switch as claimed in claim 6- wherein the adjustable stop means includes at least two disc elements, a projection extendnig from the peripheral edge of each of said disc elements, said discs having spaced open ings to coact with said last mentioned means whereby the relative spacing of the projections can be set to provide the desired limits of rotation.

8, In a miniature switch, a housing forming a chamber open at one end, a contact panel closing the open end of said chamber, a shaft rotatably mounted in said housing and extending into said chamber in overhung relation and to bring the end a predetermined spaced distance from the contact panel, a plurality of spaced stationary contacts circumferentially disposed in said contact panel a spaced radial distance from the axial line of said shaft, center contact means in said contact panel and spaced relative said stationary contacts to form an annular space therebetween, movable contact assembly means mounted on the end of said shaft and rotatable therewith and said movable contact assembly means disposed to fit into said annular space for engagement with the respective stationary contacts and center contacts on rotation of said shaft, a stop shoulder formed in said housing, adjustable stop means mounted on said shaft and adjacent the inner side of the movable contact element to coact with said stop shoulder to limit the rotation of said shaft in either direction, and means detachably connected. to said adjustable stop means and said movable contact assembly means to maintain a predetermined fixed relation therebetween to provide a desired switching arrangement on rotation of said shaft.

9. In a miniature switch as claimed in claim 8 wherein said plurality of stationary contacts are spaced at predetermined distance from each other, and spacer means between adjacent stationary contacts to provide a break before make type arrangement. 7

10. In a miniature switch, a housing forming an assembly chamber having at least oneopen end, a shaft rotatably disposed in said housing and having one end extending thercthrough into the assembly chamber, a stationary contact panel closing the open end of said assembly chamber, a plurality of stationary contact elements circumferentially disposed said contact panel, center contact means in said contact panel in the axial line of said shaft a spaced distance from each of said stationary contacts to form an annular space therebetween, carrier means mounted on the end of said shaft to fit into said annular space, contacts mounted in said carrier adapted to engage the stationary and center type contact means in assembled position and on rotation of said shaft and, detent means formed on said shaft including a circualr portion of enlarged diameter, detent elements said circular portion biased to move outwardly thereof, and a detent sleeve mounted in said chamber circumjacent the enlarged circular portion having alternatcly disposed ridges and grooves in to provide a predetermined arrangement of contact positions.

11. In a miniature switch as claimed in claim wherein the adjustable stop means includes disc means, and stops formed on said disc means for engagement with said one ridge.

12. In a. miniature switch as claimed in claim 10 wherein the adjustable stop includes, at least two disc elements, a lateral projection on each of said disc elements, and means to adjustably position said projections relative each other to provide the limit points for engagement with said one ridge.

13. In a miniature switch as claimed in claim 10 wherein the adjustable stop means includes, at least two disc elements, a projection extending from the peripheral edge of each of said disc elements, and openings formed in said disc elements to coact with said means for fixing the relative portion of said detent means, said stop means and said movable assembly whereby the relative spacing of said projection can be set to provide the desired limits of rotation.

14. In a miniature switch as claimed in claim 10 where in said plurality of stationary contacts are spaced a predetermined distance from each other, and spacer means between adjacent stationary contacts to provide a break before make type arrangement. I

15. In a miniature switch, a housing forming a chamber open at one end, a contact panel closing the open end of said chamber, a shaft rotatab-ly mounted in said housing and extending into said chamber in overhung relation to bring the end a predetermined spaced distance from the contact panel, a plurality of circumferentially spaced stationary contacts insaid contact panel disposed to extend therethrough into the chamber and parallel with the axial line of said shaft, center contact means in said contact panel disposed parallel with the axial line of said shaft and also extending into said chamber, the portion of both said stationary contacts and said center contact means extending into said chamber disposed to form an annular space therebetween, and movable contact assembly means mounted on the end of said shaft including a carrier ele ment having an annular cylindrical portion disposed to fit into said annular space in assembled position, and spaced contact means in said annular cylindrical portion adapted to engage said stationary contacts and said center contact means on rotation of the shaft, and detent means comprising an enlarged circular hub formed as an integral portion of said shaft, plural detent elements in said cylindrical portion urged to move outwardly of said circular hub, and a detent sleeve mounted in said chamber circumjacent the enlarged cylindrical portion of the shaft, alternately disposed ridges and grooves adjacent one end of said detent sleeve in the plane of movement of said detent elements and to coact therewith to permit step by step indexing of said movable contact assembly means on rotation of said shaft, at least one of said ridges extending axially beyond the end of said circular hub to form a stop, adjustable stop means mounted on said shaft between said circular hub and said movable contact assembly means to coact with said one ridge for limiting the rotation of said shaft on rotation in either direction, and an axially disposed pin means extending through said cylindrical portion said stop means and said carrier to fix their position relative each other as desired and thus provide a predetermined switching arrangement on. rotation of said shaft.

16. In a miniature switch as claimed in claim 15 wherein the adjustable stop means includes at least two disc elements, a projection extending from the peripheral edge of each of said disc elements, said discs having spaced openings to coact with said last mentioned means whereby the relative spacing of the projections can be set to provide the desired limits of rotation.

17. In a miniature switch as claimed inolaim 15 wherein said plurality of stationary contacts are spaced a predetermined distance from each other, and spacer means between adjacent stationary contacts to provide a break before make type arrangement.

18. In the combination claimed in claim 15 wherein a sealing compound is disposed to cover the exterior portion of said contact panel to provide a seal between the joint formed by the housing and panel and the joint between the contacts and panel.

References Cited in the file of this patent UNITED STATES PATENTS 2,186,638 Hall Jan. 9, 1940 2,264,045 Maier Nov. 25, 1941 2,451,176 Schellman -1 Oct. 12, 1948 2,459,998 Ellithorpe J an. 25, 1949 2,489,626 Doucette Nov. 29, 1949 2,549,998 Allison Apr. 24, 1951 2,586,892 Weber et al Feb. 26, 1952 FOREIGN PATENTS 1,128,738 France Aug. 27, 1956 

